Many medicaments and fluids are routinely infused and discharged fluids collected through a catheter system connected to the patient and a administration container or a collection container. The typical administration set has a pre-filled plastic bag or bottle connected to one end of a catheter. The catheter may be integrally formed with the bag or the bag may have a puncturable port for connection with a needle on one end of the catheter. The other end of the catheter usually has a needle/cannula for insertion into the patient intravenously or enterally.
Collection bags or containers are constructed much the same way, except that the bag or container is initially empty. To infuse or collect from a patient, the needle/cannula at the free end of the catheter is inserted through the dermal layer into the lumen of the blood vessel and taps in to the circulation system of a patient or into other parts of the body. The catheter may have a clamp or valve which is manipulated to open the passageway from the bag to the patient. Once the infusion bag is empty or the collection bag full, each may be disconnected from the patient.
The retractable cannula assembly with its contaminated needle presents the danger of an inadvertent needle stick to personnel handling the used equipment. Even trace amounts of body fluids from a person with Hepatitis, Acquired Immune Deficiency Syndrome (AIDS), and other infectious diseases, transferred into another's blood stream can transmit these diseases. Thus, what is needed in the art is a needle/cannula assembly that protects from inadvertent needle sticks.